The half million federal workers, military personnel and retirees here are counting on the Democratic-controlled House to scuttle a Senate Budget Committee plan to deny them their next pay or pension adjustment.

If the Senate Budget Committee has its way, civilian and military personnel would not get a raise this October. And retirees would not get another cost-of-living increase until March 1984. The next two adjustments for both groups would be limited to 4 percent a year.

The budget President Reagan sent Congress earlier this year anticipated a 5 percent October U.S. raise. It did not propose deferring COL raises for retirees who get their inflation catchups each March.

(White collar federal workers got a 9.1 percent raise in 1980, President Carter's last year in office, and a 4.8 percent raise last October that was less than half the military raise and well below the amount needed to provide a catchup with private industry gains. Retirees got an 8.7 percent raise last March; a 4.4 percent raise in March, 1981; a 6 percent COL increase in March 1980 and another 7.7 percent inflation catchup in September of 1980, the last time retirees were allowed two adjustments in one year).

Federal union leaders and retiree groups believe the House will block the Senate's pay/pension freeze. If not, they hope to find a member brave enough to propose that Social Security raises (which are not frozen under the Senate plan) be subject to the same limits put on U.S. retiree adjustments. That would be one way to kill off the freeze idea this election year since one of every six Americans now draws some form of Social Security payment.

Although key career federal officials have diplomatically warned the White House about putting too much pressure on feds, many of the president's political advisers discount the power of the "bureaucratic vote" outside of metro Washington, where members of Congress are elected, or not elected, by people who work for the government.

Surveys indicate that retired government workers voted overwhelmingly for Reagan, based on his promise (later broken) not to take away their twice yearly COL raises. There are 20 states with more than 30,000 federal civilian retirees or survivors, and U.S. retirees provide the swing vote in many congressional districts in Maryland, Virginia, Florida, California and Arizona.

An administration official yesterday said that he does not "buy the idea that the federal employe/retiree vote is a monolith" or, if it is, that it has that "much impact" outside of the Washington area. "If people are concerned about inflation, and even the Democrats in Congress have learned about the evils of deficits, they will understand that sacrifices are in order," he said.

He noted that for much of 1980 Carter aides hinted feds might not get any pay raise "then the president gave them a 9.1 percent increase in a year when inflation was running over 13 percent. By the way," he noted, "Carter lost," which says something--although he admitted he did not know what--about the federal employe/retiree vote.

Leaders of federal unions and retiree groups will zero in on Republican House members in states with big federal/retiree populations. Several states-- California, New York, Pennsylvania, Texas, Ohio, Maryland and Virginia--have more than 100,000 feds, and they are the dominant voter bloc in some districts in Florida, Oklahoma and Utah.

They will be reminding Democrats and Republicans in the House--all of whom are up for reelection--of their federal constitutents in the weeks ahead.